An interventional study of Combined MK-7 + vitamin D3 drops and Vitamin D3 Drops in Infant Vitamin K Status and Vitamin K Deficiency Bleeding, sponsored by Norfolk and Norwich University Hospitals NHS Foundation Trust. Not yet recruiting. Open to participants aged Up to 7 Days, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-04.
Sponsored by Norfolk and Norwich University Hospitals NHS Foundation Trust · Not applicable, Interventional, and Prevention
The OK Daily Study is a multi-centred, part-randomised, part blinded, four cohort study. We are exploring daily dietary supplementation with vitamin K2, specifically menaquinone-7 (MK-7), given to breastfed infants or breastfeeding mothers to see whether this improves the incidence of biochemical vitamin K deficiency in the infants at 2 months postnatal age.
The overall aims are:
Once recruited, mother and infant pairs will be grouped initially based on the families' feeding choice. Breastfed infants will then be randomised 2:1 to the infant supplementation or maternal supplementation group. Within the infant supplementation group, infants will either receive MK-7 with vitamin D or a placebo containing vitamin D.
Follow up will occur at 2 months postnatal age (range 2-3 months postnatal age), where bloods and breastmilk samples will be collected to assess the infant and maternal vitamin K status.
The OK Daily Study is a multi-centre study taking place in the Norfolk and Norwich University Hospital, Norwich, UK, and Ashford and St Peters' Hospital, Chertsey, UK.
Infants born at ≥37 weeks' gestation will be recruited in the participating site if they meet eligibility criteria and are born within the recruitment window. Recruitment will take place before the mother and infant are discharged from the hospital following birth.
The two main arms of this study are breastfeeding and formula feeding. Mother and infant pairs will initially be allocated based on the family's feeding preferences.
Infants in the breastfeeding arm will be randomised into group 1 or group 2 in a 2:1 ratio. Group 1 allocation will be blinded; group 2 allocation will be open label.
Formula fed infants will be in group 3 and will not require any additional supplementation as part of this study. This is because infant formula is already supplemented with adequate amounts of vitamin K1 and vitamin D.
All supplements will be started within 7 days of birth. Vitamin D drops are included for breastfed infants as per national UK guidelines.
Follow up will be as follows:
1 month postnatal visit (range 1-1.5 months) - phone call.
o Confirmation of eligibility to continue, assessment of compliance with the intervention, and to schedule the in person follow up visit
2 months postnatal (range 2-3 months) - in person visit.
Blood samples will be analysed for vitamin K status, including Proteins Induced by Vitamin K Absence/antagonism of prothrombin (PIVKA-II) and of osteocalcin (undercarboxylated osteocalcin), dephosphorylated-undercarboxylated matrix gla-protein (dp-ucMGP) and serum vitamin K concentrations (including of vitamin K1 and MK-7). Breastmilk samples will be analysed for vitamin K concentrations (including vitamin K1 and MK-7)
Once this in person follow up visit has been completed, the mother and baby pair will have completed the study.
1,081 studies on the registry are indexed under Breast Feeding; 217 are open to participants now.
This study's planned enrollment of 134 is above the median of 100 across 844 interventional studies indexed under Breast Feeding.
Browse Breast Feeding studies →Norfolk and Norwich University Hospitals NHS Foundation Trust is the lead sponsor of 30 studies on the registry; 9 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Group 1 = infant supplementation group. Infants in this group will be randomised to receive either 6 drops a day containing 45 micrograms/day of MK-7 plus 10 micrograms/day vitamin D3 OR 10 micrograms/day vitamin D3 only (the active placebo, containing no vitamin K) Group 2 = maternal supplementation group. Mothers in this group will be given 2 mg/day MK-7 capsules. Infants in this group will receive 10 micrograms/day vitamin D3.
Other: Combined MK-7 + vitamin D3 drops · Other: Vitamin D3 Drops · Other: MK-7 capsules
Infants who are exclusively formula feeding. These infants will receive the recommended daily amount of vitamin K through their formula milk intake and so will not receive any additional vitamin K supplementation.
Other: Vitamin D3 Drops
6 drops/day providing 45 micrograms/day MK-7 plus 10 micrograms/day of vitamin D3
Also known as: Vitamin K2 supplemented infant group
6 drops/day providing 10 micrograms/day vitamin D3 and no supplementary MK-7.
Also known as: Vitamin K2 unsupplemented group
1 mg capsules of menaquinone-7, with a daily dose of 2 mg (i.e. 2 capsules per day)
Comparison of the proportion of participants who have a PIVKA-II >0.05 AU/mL in the unsupplemented and supplemented infants.
PIVKA-II = protein induced by vitamin K antagonism/absence; clotting protein II. Measured via serum blood sample in arbitrary units/mL. For the primary outcome, this is the comparison between the supplemented and unsupplemented infants.
Time frame: 2 months postnatal age (range 2-3 months).
Comparison of the proportion of participants who have a PIVKA-II >0.05 AU/mL in the various study groups.
PIVKA-II = protein induced by vitamin K antagonism/absence; clotting protein II. Measured via serum blood sample in arbitrary units/mL. For secondary outcome, this is comparison between remaining groups, other than those assessed in the primary outcome measure.
Time frame: 2 months postnatal age (range 2-3 months).
Comparison of serum levels of osteocalcin (undercarboxylated and carboxylated) between the study groups.
Both undercarboxylated and carboxylated levels of osteocalcin will be measured in nanograms/mL.
Time frame: 2 months postnatal age (range 2-3 months).
Comparison of the percentage of undercarboxylated osteocalcin as a proportion of total osteocalcin (%GluOC) between the study groups.
Total osteocalcin calculated by the sum of the undercarboxylated and carboxylated osteocalcin values.
Time frame: 2 months postnatal age (range 2-3 months).
Comparison of serum levels of dephosphorylated undercarboxylated matrix Gla Protein in included participants between the study groups.
Measured in picomol/mL
Time frame: 2 months postnatal age (range 2-3 months).
Comparison of levels of serum K vitamers (including, but no limited to, vitamin K1 and menaquinone-7) between the study groups.
Serum K vitamers will be reported in micrograms/mL.
Time frame: 2 months postnatal age (range 2-3 months).
Comparison of the levels of breastmilk K vitamers (including, but not limited to, vitamin K1 and menaquinone-7) between unsupplemented and supplemented mothers.
Serum K vitamers will be reported in nanograms/mL
Time frame: 2 months postnatal age (range 2-3 months).
Investigation of percentage compliance to study supplementation.
Amount of remaining supplement will be assessed at follow up. This will then be used to calculate percentage compliance by comparing it to the expected volumes.
Time frame: 2 months postnatal age (range 2-3 months).
Investigation regarding families' opinions about infant and maternal vitamin supplementation.
Measured via verbal questioning at follow up.
Time frame: 2 months postnatal age (range 2-3 months).
No study locations are listed for this record.
Start is estimated for Oct 2026; primary completion for Sep 2027, 11 months later.
Of 502 non-industry interventional studies with no phase under Breast Feeding, half reached primary completion within 12 months of starting (the median), counting those still running; a quarter within 6 and three quarters within 23. This study's planned 11 months is close to that.
Counting every sponsor, half of 510 studies reached it within 12 months; a quarter within 6 and three quarters within 23.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Norfolk and Norwich University Hospitals NHS Foundation Trust